The Delhi Sultanate is a term used to cover five short-lived, Delhi based kingdoms or sultanates, of Turkic origin in medieval India. The sultanates ruled from Delhi between 1206 and 1526, when the last was replaced by the Mughal dynasty. The five dynasties were the Mamluk dynasty (1206–90); the Khilji dynasty (1290–1320); the Tughlaq dynasty (1320–1414); the Sayyid dynasty (1414–51); and the Lodi dynasty (1451–1526).

Qutb-ud-din Aibak, a former slave (Mamluk) of Muhammad of Ghor, was the first sultan of Delhi and his dynasty managed to conquer large areas of northern India. Afterwards the Khalji dynasty was also able to conquer most of central India, but both failed to unite the Indian subcontinent. The sultanate are also noted for being one of the few states to repeatedly defeat the Mongol Empire.

The Sultanate ushered in a period of Indian cultural renaissance. The resulting "Indo-Muslim" fusion of cultures left lasting syncretic monuments in architecture, music, literature, religion and clothing. It is surmised that the Urdu language (literally meaning "horde" or "camp" in various Turkic dialects) was born during this period as a result of the intermingling of the local speakers of Sanskritic Prakrits with immigrants speaking Persian, Turkic and Arabic under the Muslim rulers. The Delhi Sultanate is the only Indo-Islamic empire to have enthroned one of the few female rulers in India, Razia Sultana (1236–1240). In 1526 the Delhi Sultanate was absorbed by the emerging Mughal Empire.

Delhi (/ˈdɛli/; locally pronounced Dillee or Dehli), officially the National Capital Territory of Delhi (NCT), is the largest metropolis by area and the second-largest metropolis by population in India. It is the eighth largest metropolis in the world by population with 16.7 million inhabitants in the Territory at the 2011 Census. The region has been given special status of National Capital Region under The Constitution (69th Amendment) Act, 1991. There are nearly 22.2 million residents in the greater National Capital Region urban area (which also includes the cities Noida, Greater Noida, Ghaziabad, Gurgaon,Sonepat and Faridabad along with other smaller nearby towns).

Delhi is known to have been continuously inhabited since at least the 6th century BCE, though human habitation is believed to have existed since the second millennium BCE. Delhi is also widely believed to have been the site of Indraprastha, the legendary capital of the Pandavas during the times of the Mahabharata. Delhi re-emerged as a major political, cultural and commercial city along the trade routes between northwest India and the Gangetic plain after the rise of the Delhi sultanates. It is the site of many ancient and medieval monuments, archaeological sites and remains.